<?php
/**
 * Created by PhpStorm.
 * User: 764432054@qq.com
 * Date: 2020/3/11
 * Time: 9:57
 */
$data='abc';
$pdata=pack('a*',$data);


$undata=unpack('a2',$pdata);
var_dump($undata);



$num=200;
$pnum=pack('N',$num);
var_dump($pnum);

$up_num=unpack('Nlen',$pnum);
var_dump($up_num);